Fix bug preventing database from being recreated (#3962)

(cherry picked from commit 265d0e6)

plugins/outputs/influxdb/influxdb.go

@@ -210,7 +210,7 @@ func (i *InfluxDB) Write(metrics []telegraf.Metric) error {
 		}
 
 		switch apiError := err.(type) {
-		case APIError:
+		case *APIError:
 			if !i.SkipDatabaseCreation {
 				if apiError.Type == DatabaseNotFound {
 					err := client.CreateDatabase(ctx)

plugins/outputs/influxdb/influxdb_test.go

@@ -2,11 +2,13 @@ package influxdb_test
 
 import (
 	"context"
+	"net/http"
 	"testing"
 	"time"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
+	"github.com/influxdata/telegraf/metric"
 	"github.com/influxdata/telegraf/plugins/outputs/influxdb"
 	"github.com/stretchr/testify/require"
 )
@@ -37,7 +39,7 @@ func (c *MockClient) CreateDatabase(ctx context.Context) error {
 func TestDeprecatedURLSupport(t *testing.T) {
 	var actual *influxdb.UDPConfig
 	output := influxdb.InfluxDB{
-		URL: "udp://localhost:8086",
+		URL: "udp://localhost:8089",
 
 		CreateUDPClientF: func(config *influxdb.UDPConfig) (influxdb.Client, error) {
 			actual = config
@@ -46,7 +48,7 @@ func TestDeprecatedURLSupport(t *testing.T) {
 	}
 	err := output.Connect()
 	require.NoError(t, err)
-	require.Equal(t, "udp://localhost:8086", actual.URL.String())
+	require.Equal(t, "udp://localhost:8089", actual.URL.String())
 }
 
 func TestDefaultURL(t *testing.T) {
@@ -70,7 +72,7 @@ func TestConnectUDPConfig(t *testing.T) {
 	var actual *influxdb.UDPConfig
 
 	output := influxdb.InfluxDB{
-		URLs:       []string{"udp://localhost:8086"},
+		URLs:       []string{"udp://localhost:8089"},
 		UDPPayload: 42,
 
 		CreateUDPClientF: func(config *influxdb.UDPConfig) (influxdb.Client, error) {
@@ -81,7 +83,7 @@ func TestConnectUDPConfig(t *testing.T) {
 	err := output.Connect()
 	require.NoError(t, err)
 
-	require.Equal(t, "udp://localhost:8086", actual.URL.String())
+	require.Equal(t, "udp://localhost:8089", actual.URL.String())
 	require.Equal(t, 42, actual.MaxPayloadSize)
 	require.NotNil(t, actual.Serializer)
 }
@@ -90,15 +92,15 @@ func TestConnectHTTPConfig(t *testing.T) {
 	var actual *influxdb.HTTPConfig
 
 	output := influxdb.InfluxDB{
-		URLs:             []string{"http://localhost:8089"},
+		URLs:             []string{"http://localhost:8086"},
 		Database:         "telegraf",
 		RetentionPolicy:  "default",
 		WriteConsistency: "any",
 		Timeout:          internal.Duration{Duration: 5 * time.Second},
 		Username:         "guy",
 		Password:         "smiley",
 		UserAgent:        "telegraf",
-		HTTPProxy:        "http://localhost:8089",
+		HTTPProxy:        "http://localhost:8086",
 		HTTPHeaders: map[string]string{
 			"x": "y",
 		},
@@ -133,3 +135,51 @@ func TestConnectHTTPConfig(t *testing.T) {
 
 	require.Equal(t, output.Database, actual.Database)
 }
+
+func TestWriteRecreateDatabaseIfDatabaseNotFound(t *testing.T) {
+	var createDatabaseCalled bool
+
+	output := influxdb.InfluxDB{
+		URLs: []string{"http://localhost:8086"},
+
+		CreateHTTPClientF: func(config *influxdb.HTTPConfig) (influxdb.Client, error) {
+			return &MockClient{
+				CreateDatabaseF: func(ctx context.Context) error {
+					createDatabaseCalled = true
+					return nil
+				},
+				WriteF: func(ctx context.Context, metrics []telegraf.Metric) error {
+					return &influxdb.APIError{
+						StatusCode:  http.StatusNotFound,
+						Title:       "404 Not Found",
+						Description: `database not found "telegraf"`,
+						Type:        influxdb.DatabaseNotFound,
+					}
+				},
+				URLF: func() string {
+					return "http://localhost:8086"
+
+				},
+			}, nil
+		},
+	}
+
+	err := output.Connect()
+	require.NoError(t, err)
+
+	m, err := metric.New(
+		"cpu",
+		map[string]string{},
+		map[string]interface{}{
+			"value": 42.0,
+		},
+		time.Unix(0, 0),
+	)
+	require.NoError(t, err)
+	metrics := []telegraf.Metric{m}
+
+	createDatabaseCalled = false
+	err = output.Write(metrics)
+	// We only have one URL, so we expect an error
+	require.Error(t, err)
+}